As one example of a power supply for generating an AC (alternating current) voltage, there is a type based on a system designed to convert a voltage held by electric energy storage means such as a capacitor, through a DC-DC converter and an inverter.
FIG. 1 illustrates a typical circuit configuration of such an AC power supply. This electric energy storage apparatus comprises: electric energy storage means; a discharge circuit; a DC/DC converter; and an inverter.
Generally, when a certain electronic device is operated by electric power, it is necessary to supply electric power within a predetermined operating voltage range which is determined by characteristics of the device. This is because, although an electronic device can adequately operate within a predetermined voltage range depending on individual characteristics of the device, it becomes operationally unstable or becomes non-operative if a supply voltage changes to a value out of the operating voltage range. Therefore, in the above AC power supply, it is essential to perform control for allowing an output voltage therefrom to fall within a certain range, primarily based on the DC-DC converter.
Patent Document 1: JP 2008-219964 A
Patent Document 2: JP H06-225462 A
Patent Document 3: JP S54-126931 A
Patent Document 4: U.S. Pat. No. 3,100,851 B
Patent Document 5: JP 2007-166691 A
Patent Document 6: JP H07-115728 A
Patent Document 7: JP 2002-345157 A